Esters of methacrylic acid



Patented Sept. 13,

UNITED STATES PATENT OFFICE ESTERS OF METHACRYLIC ACID of Delaware No Drawing.

Application July 14, 1934,

Serial No. 735,278

6 Claims.

The present invention relates to new composttions of matter, to methods for their preparation, and more particularly to the methacrylic acid esters of the alicyclic alcohols.

An object of the present invention is to provide new compositions of matter and a process for their preparation. A further object of the invention is to provide a new polymerizable composition of matter together with a process for its polymerization. A still further object of the invention is toprovide a-process for the preparation of the methacrylic acid esters of the alicyclic alcohols which may be obtained by the ester interchange method of interacting a lower alkyl ester of methacrylic acid with the alcohol in the presence of a suitable catalyst or by the reaction of the alcohol with a methacrylyl halide. Another object of the invention is to provide mix tures or interpolymers of the polymerized resin with other polymerizable compounds of methacrylic and acrylic acids. Other objects and advantages of the invention will hereinafter appear.

There have been prepared in accord with this invention valuable esters of methacrylic acid which have been found useful as prepared and even more valuable when polymerized. These compounds may be generally described as methacrylic acid esters of the alicyclic alcohols, such, for example, as tetrahydrofurfuryl alcohol, cyclohexanol, decahydrobetanaphthol, decahydroalphanaphthol, alicyclic tetrahydrobetanaphthol, 1, 2, or 3-alkyl substituted cyclohexanols, naphthenyl alcohols, betacyclohexyl ethyl alcohol; the alkyl or aryl substituted tetra or decahydroalpha or beta-naphthols, such, for example, as alphamethyldecahydrobetanaphthol, alphaphenyltetrahydrobetanaphthol; naphthanyl; abietyl alcohol and equivalent and homologous alcohols.

The following specific examples are furnished to illustrate methods of preparing the new compositions of matter but it will be understood that the invention is not limited to the details thereingiven.

Example 1.200 parts of cyclohexanol, 800 parts of methyl methacrylate, 450 parts of benzene, 48 parts of hydroquinone, and parts of p toluenesulfonic acid (tech) (all parts are by weight) are mixed and warmed on the water bath until solution is complete. heated on an oil bath which was maintained at a temperature of 130-140 C. under a 48" fractionating column fitted with a condenser arranged for controlled reflux. The distillate, which consisted of a benzene-methanol binary, was collected at such a rate that the tempera- The solution was then ture at the head of the column remained at 58-59. Heating was continued until the temperature at the head of the column could not be maintained at 58-59". The progress of the reaction was followed by measuring the amount of methanol in the distillate as shown by the portion that would dissolve in water. The cold reaction mixture was neutralized and then washed. and dried over a suitable desiccating medium. The solvents were removed from the dried product by fractional distillation, and the ester finally separated by fractionation under reduced pressure. A 62% yield of cyclohexyl methacrylate was obtained, which had a boiling point of ll-74 C. at 5 mm., a density at C. of 0.959, and a saponification number of 322, (theoretrical 332).

Example 2.'I'he process of Example 1 was repeated with 800 parts of methyl methacrylate, 200 parts of tetrahydrofurfuryl alcohol, 700 parts of benzene, parts of hydroquinone, and 5 parts of sulfuric acid (concentrated). The temperature of the oil bath was maintained at approximately 140-1 55 C. and after 16 hours a 44% yield of tetrahydrofurfuryl methacrylate was obtained having a boiling point of 81-85 C. at 4 mm., a density at 20 C. of 1.039, and a saponification number of 326, (theoretical 330).

Example 3.'I'he process of Example 1 was repeated with 330 parts of methyl methacrylate, parts of decahydrobetanaphthol, 275 parts of benzene, 20 parts of hydroquinone, and 10 parts of p-toluene sulfonic acid 4H2Q. The temperature of the oil bath was maintained at approximately -145 C. and after 21 hours a 77% yield of decahydrobetanaphthyl methacrylate was obtained, which had a density at 20 C. of 0.998.

Example 4.--128 parts of naphthenyl alcohols, 2'75 parts of methyl methacrylate, 225 parts of benzene, 20 parts of hydroquinone, and 2 parts of concentrated sulfuric acid were mixed and warmed on the water bath until solution was complete. The solution was then'heated on an oil bath which was maintained at a temperature of 130-140 C. under a 48" fractionating column fitted with a condenser arranged for controlled reflux. The distillate, which consisted of a benzene-methanol binary, was collected at such a rate that the temperature at the head of the column remained at 58-59. Heating was continued until the the temperature at the head of the column could not be maintained at 58-59". The progress of the reaction was followed by measuring the amount of methanol in the distillate as shown by the portion that would dissolve in water. The cold reaction mixture was dried over a suitable desiccating medium, the solvents removed by fractional distillation and the resulting mixture fractionated under reduced pressure. An 86% yield of naphthenyl methacrylate was obtained, which had a saponification number or 234, and a density at 20 C. 01' 0.928.

Other methods may, of course, be employed for the preparation of the enumerated methacrylates, such, for example, as are disclosed in the copending applications of Barrett and Strain, Serial Nos. 735,274, 735,276, and 735,279 or by any of the well known esterification or ester interchange proc-' esses.

The methacrylates as prepared in accord with the examples are usually mobile liquids, but may sometimes be solids. are monomeric and may be polymerized, according to the invention, by means of heat, light and/or a catalyst, e. g. as described for the polymerization of organic vinyl esters in British specification 15271/ 1914. Preferably a catalyst such as oxygen, ozone, an organic peroxide, an ozonide, etc. is employed. Other catalysts which may be usedv include aluminum sulfate, boron fluoride, the mineral acids, e. g. hydrochloric and sulfuric acids as well as the organic acids, for example, acetic, methacrylic acids, etc., as well as the anhydrides and. acid halides of such organic acids; metal salts of fatty acids and resinic acids, e. g. cobalt linoleate and resinate, manganese oleate and rosin, etc. The polymerization may be effected in the presence or absence of a solvent for both monomer and polymer, or in the presence of a solvent for both monomer and polymer, or in the presence of a solvent for the monomer and a non-solvent for the polymer, or the monomer may be emulsified and then polymerized. Preferably polymerization is carried out at a moderate temperature, i. e. between 60-100 C., altho higher temperatures, such as, for example, 130 C., or higher, may be employed. The polymerization reaction is usually strongly exothermic and it may be necessary to control the temperature by cooling devices, tho polymerization may be carried out in apparatus which may be or may not be provided with condensing devices or in suitable pressure equipment.

As indicated, various methods may be employed for polymerizing the monomeric estersof methacrylic acid and it has been found that the properties of the resins, the physical properties to a large extent and the chemical properties to a lesser extent, are altered considerably by the type of polymerizing process utilized. The process described in the copending applications of D. E. Strain, Ser. Nos. 668,080 and 704,753, may be used, if desired.

Methods illustrating the polymerization of the esters will now be described, but it will be understood that other suitable polymerizing processes may be employed.

Ewample 5.100 parts (parts are given by weight) of cyclohexyl methacrylate monomer was dissolved in 400 parts of methanol in a bottle provided with a stopper, then 1 part of powdered benzoyl peroxide added to this solution. After the benzoyl peroxide was all dissolved, parts of water, insufficient to cause permanent turbidity, was added. The bottle was securely closed and set in an oven at approximately 65 C. After the polymerization was complete in approximately 2 days, the mixture was allowed to cool. The product was filtered, washed with a little cold methanol, and dried in a vacuum desiccator. The

The esters as thus produced polymer was obtained in 93% yield as a white coarse powder. The polymer is soluble in butyl acetate and toluene, and relatively insoluble in gasoline and acetone. It has a viscosity of 0.065 poise (5% solution in toluene at 25" C.) and is compatible with nitrocellulose. The resin was placed in a disk shaped mold in which it was sub-- jected to a temperature of 160" C. and a pressure of approximately 4000 pounds per square inch for approximately 15 minutes. A molded clear, colorless, strong disk was obtained which softened at a temperature of C. The compatibility with nitrocellulose was determined by dissolving an equal volume of a 5% toluene solution of the polymerized ester in a solution consisting of 20 parts of nitrocellulose and 380 parts of butyl acetate. The resulting solution was spread on a glass plate and allowed to dry at room temperature.

Example 6.The polymerization process of Example 5 was repeated using parts of tetrahydrofurfuryl methacrylate monomer, 250 parts of methanol, 1 part of benzoyl peroxide, and 54 parts of water. After 3 days at 65" C. an 86% yield of the polymer as a fused, brittle, glassy mass was obtained, which was recovered by decanting Y the liquid, removing the polymer from the bottle. and after cutting into small pieces drying in a vacuum desiccator. The polymer was relatively insoluble in butyl acetate, gasoline, acetone, and

toluene. The resin was placed in a disk shaped mold in which it was subjected to a temperature of 100 C. and a pressure of approximately 4000 pounds per square inch for approximately 15 minutes. A molded, slightly amber-colored disk was obtained which softened at a temperature of 60 C.

Example 7.Undiluted decahydronaphthyl methacrylate monomer containing 1.9% benzoyl peroxide was heated to a temperature of 100 C. After 2 days a 91% yield of polymer was obtained which upon extraction with methanol gave a gray, sandy-like powder. The polymer is soluble in butyl acetate, gasoline, and toluene, and relatively insoluble in acetone. It has a viscosity oi. 0.02 poise (5% solution in toluene at 25 C.). The resin was placed in a disk shaped mold in which it was subjected to a temperature of C. and a pressure of approximately 4000 pounds per square inch for approximately 15 minutes. A

molded transparent, brown, brittle disk was obtained which softened at a temperature of 75 C.

Example 8.--Undiluted naphthenyl methacrylate monomer containing 1.6% benzoyl peroxide was heated to a temperature of 65 C. for 14 hours and at 100 for 24 hours. A 90% yield of the polymer was obtained as a brown, transparent, slightly soft and sticky fused mass. It is soluble in butyl acetate, gasoline, and toluene, and relatively insoluble in acetone. Ithas a viscosity of 0.02 poise (5% solution in toluene at 25 C.), and is compatible with nitrocellulose which was determined as in Example 5.

Valuable products may be obtained by utilizing the polymers of the esters described herein together with equivalents or homologues thereof admixed with other polymeric acrylic or methacrylic esters or other derivatives. Especially valuable products result if the monomeric esters are mixed and then polymerized. By this method interpolymers having a wide range of characteristics are made. Due to the unique characteristics of methyl methacrylate polymer, which is a hard resin having a high melting point, its admixture with the polymeric esters of advantageous to have presentplasticizers'to alter stance one of steel or glass, so that the articles,

methacrylic acids herein described or interpolymers thereof are particularly 'well adapted'ior many uses.

The polymerized esters of methacrylic acid, as well as mixtures QrinterpoIymers thereof with other p'olymerizable compounds, are particularly well suited for thermoplastic molding. The monomer may bepolymerized and/or reformed prior to placing in the mold and then'may be molded in accord with the usual procedural steps emplqycd, particularlyin the molding of methyl methacrylate as described in the Rowland Hill Patent 1,980,483 of. Nov. '13, 11934. The mold preferably ishot, prior to the. introduction of the polymerization product, isthen'closed andthe material so confined heated and pressed, the.

temperatures ranging from. approximately 80-150 0., and pressures from 200 pounds per square inch upward. are usually sufficient to give a suitably molded product; The presence or absence of plasticizers will, of course, alter considerably the molding conditionsgan'dit is usually the physical characteristics of the resultin'gjprom uct to fit the particularfneed for =.which'.the v v i v 9 ljm. may notv :beeva'porated whiIe-i'another portion may. be, converted into 'ithe solid polymerization product. "The articles. thus-treat d have 1mg parted to them a very high res'l'stance-to-extemalinfluences, e. g. resistance to-wa'ter, acids, alkalis. 1 v and atmospheric changes. ff I The syrupy mass' can'bemixedwith .com -P minuted matter,. such, forinstance, as, ground;

molded article is to be-usedh; The masses resulting frornfpolymerizatlon can immediately (i. ,e. in the jstate the'yih'ave. been" obtained) 'be made intojusefulf articles. It is.

possible to obtain the reduired articles'if, for instance, the polymerization, carried outwhile' 1 the initial material is in asuitabl mold}, for in- .for example, umbrella handles, fountain penbar rels, buttons, and'the like, ,areobtained directly .from the mold,. v0r, if desired the. masses may be worked to the required shape byjsoftening with suitable softeners Or -plasticizers, in :the presence of volatile solvents andvafterfshflpm evap orating the solvent.

"The polymerization iworked solid, or plastic polymerization productsfof .the

S into the required shapes in: various'ways'; for exe ample, they canibe softened'and lme'aded; rolled, compressed, drawn into, wires, threads, or the r" like, or the masses can be" mixed with'fadditional substance and rolled into plates, or flln is jor they may be pressed intothe: required Jshape's; :suchasg' T verted in'to the SoIidla'cqur-formIRi i 1 It is obvious that mixtures or various poly- 1m1erlzed' methacrylic acid esters, can be used'for. ,lacquering, painting,v or impregnating. in accordf;ance with this invention. It "is likewise obvious that li ql y'orlpa t y po ymerized esters can 'be'mixed'with suitable additional substances to buttons;combs,'andthe like, v

The solid masses can be worked by cutting,

sawing, filing, or the like, 'whether'athybe obtained' directly by polymerization, or afterspecial treatment of. the polymerized masses.

cryllc acid ester.

The polymerization product moivu'in; a suit-- able solvent which may or may not be the mono-'- mer maybe transformed into a useful article, e. g. films, by casting and then evaporatingthe solvent," or by extruding thru a-suitable orifice into a precipitating batho'r. drying atmosphere.

The polymer may be recovered from such solutions by precipitationfwithla. suitable non-solvent for the polymer.

The properties of the resulting masses may be widely varied by modiijication -with fplasticizers, e. g. dibutyl phthalate, .tricresylphosphataetcg,= drying, semi-dryingjg'and'nondrying oils, syn- .thetic and natural resins, waxes, bitumens," cellulose derivativeafe. g. cellulose nitrate and ethyl cellulose, etc.,- pigments, fillers, and dyes, etc.

' Thus it is possible to produce, instead of hard glass-like masses, also soft'and flexible masses.

product.

heating them by themselves, :or with suitable solvents; and 'using them in their; softened state.

.onfcoolingflor on theevaporationofthediluent "that "mayqfstill" be present, the product is con;

or during the polymerizing process. or the addi- 5 tions can be made to the alreadyformed polymerization productsin a suitable condition.

If the polymerization of an organicmethacrylic acid ester be carried out in an incomplete manner, afsyrupy solution of the polymerization product containing some unchanged methacrylic acid ester is. obtained.- This product can be utilized 'either'idirectly'or along with other solvents or diluents for the production of substances to. v be. used" for coating, painting ,or' impregnating 15 purposes; if, for instance, aporous substance such as wopd, paper; textile fabrlc, artificial stone, orv the like be coated with the said syrupysolution or be impregnated therewith, veryresistant coatings and impregnations are obtained. oncompleting-the polymerization-of the coating, painting or'impregnation, -ior in'st'ance, by exposing the article to artificial or" natural light, or by In this cd'se-a-portion 0f the-unchanged 'metha 1uuou..-ma or fcork, or ground wood, fibrous substanceafmineral fillers, or the like; and the mixture be madeinto the proper shape"-a'ncl'thef unchanged methacrylic acid esters in" the "article's "be convertedby suitable" polymerization into the. -j solid flnal "It is also ptsib1ewsaa immsous, semimethacrylic, 'acid' esters, "these being softened by ,modifythe properties of the]acquering,- painting, or impregnating materials in any desired nian- Iher.A ;additionsmrtms'm d oils's hould be nientioned'isuch, for'i'n'stance, ascastor. oil) dyes, powdered substances. (such. asfzinc oxide), cam- 'fphor',-oamplior substitutes, andthe like.

qInaccordance with this invention it is possible to obtain valuable products ifythe said'polymers be dissolved or softened in suitable solvents and jthen be' converted again'to the solidstate. The products thus obtained maybe used for purposes for which cellulose esters have hitherto, been used,

namely, as substitutes for horn, amber; artificial resins, lacquers, for impregnating- 3 and 1' 9. 50, for .fl aPmdueum-br mmaz nterisyer ,for-

sa ety, lass, press re adh sive a ifi ial threads.

and'thelikafl. v i A "I'heproducts thus formed have the advantage over products madefrom nitrocellulose in' being less inflammable.- Bythe addition of'suitable agentathe strength and bardnessof the The monomer may be polymerized in the pres-' ence of a solvent and the solution used as such or the polymer recovered from the solution by evaporation or precipitation methods. In many it) cases, however, it is more profitable to use an amount of solvent insuflicient to produce a freely flowing solution, so that soft plastic masses are obtained which can be pressed, kneaded, rolled or drawn mto shape, or formed into blocks, plates,

or films.

Plasticizers or other modifying agents may be added to the m' iomer prior to polymerization or directly to the polymerized product, it being generally desirable to employ a plasticizer which is soluble in the polymer and the monomer, altho it is not essential that the dual solubility characteristics be present. Thus, plasticizers or softening agents, such as, for example, camphor; phthalates, such as ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexyl, methyl cyclohexyl, or benzyl phthalate or phthalates of the mixed types such as cyclohexyl butyl, benzyl butyl or butyl lauryl phthalate; esters of other dibasic acids, such as the ethyl, propyl, isopropyl, butyl, isobutyl, cyclohexyl, methyl cyclohexyl or benzyl esters of succinic, fumaric, tartaric, adipic and sebacic acids; esters of monobasic acids, such as the butyl, isobutyl, cyclohexyl, methyl cyclohexyl, benzyl or lauryl esters of lauric, laevulinic, benzoic, benzoyl 35 propionic and benzoyl benzoic acids; esters of polyhydric alcohols, e. g. glycol and glycerol, such as glycol benzoate, glycol laevulinate, triacetin tripropionin and tributyrin; substituted toluene sulphonamides, such as ethyl paratoluene sulphonamide; substituted amides, such as tetraethyl phthalamide, tetrabutyl succinamide, tetrabutyl adipamide, tetraethyl phthalamide; hydrocarbons, such as dixylyl ethane; halogenated hydrocarbons, such as chlorinated diphenyls and dichlordibenzyl; ether compounds such as dicresoxy ethyl ether; and drying, non-drying, or semi-drying oils, such as castor oil, cotton seed oil, linseed oil, and the like. These additions also facilitate later mechanical treatment, as cutting, sawing, and polishing.

The polymerized esters, mixtures of the polymerized esters with dissimilar polymerizable esters or other polymerizable compounds of methacrylic or acrylic acids, or vinyl compounds, or interpolymers of the esters with such other compounds, may be used advantageously as safety glass interlayers. These polymerized esters, mixtures thereof, or interpolymers thereof may be plasticized or otherwise modified as desired, The compositions may be compounded with glass in an unpolymerized, partially polymeriud, or completely polymerized condition. when compounding the safety glass with the unpolymerized or partially polymerized compositions, the polymerization maybe effected by subjecting the sandwich of glass and compound to suitable application of light and/or heat.

- From a consideration of the above specification it will be realized that various changes may be made in the process or product without departing from the invention or sacrificing any of its advantages.

We claim: v

1. The polymeric methacrylic acid ester of an alcohol selected from the group consisting of an alicyclic alcohol and tetrahydrofurfuryl alcohol, in which there is no branch-chain substitution on the carbon atom adjacent to the carbinol group, prepared by heating the monomeric ester to a temperature of from to C., in the presence of benzoyl peroxide.

2. The polymeric cyclohexyl methacrylate prepared by heating monomeric ester to a temperature of from 60 to 100 C., in the presence of benzoyl peroxide.

3. The polymeric tetrahydrofurfuryl methacrylate prepared by heating the monomeric ester to a temperature of from 60 to 100 C., in the presence of benzoyl peroxide.

'4. The polymeric decahydrobetanaphthol methacrylate prepared by heating the monomeric ester to a temperature of from 60 to 100 C., in the presence of benzoyl peroxide.

5. The molding. composition comprising the polymeric methacrylic acid ester of an alicylic alcohol selected from the group consisting of an alicyclic alcohol and tetrahydrofurfuryl, alcohol, in which there is no branch-chain substitution on the carbon atom adjacent to the carbinol group,

prepared by heating the monomeric ester to a temperature of from 60 to 100 C., in the presence of benzoyl peroxide.

6. The interpolymer of a methacrylic acid ester of an alcohol selected from the group consisting of an alicyclic alcohol and tetrahydrofurfuryl alcohol, in which there is no branch-chain substitution on the carbon atom adjacent to the carbinol group, and a polymerizable derivative of an acid selected from the group consisting of acrylic acid and methacrylic acid, which interpolymer is prepared by heating a mixture of the monomeric compounds to a temperature of from 60 to 100 0., in the presence of benzoyl peroxide,

HAROLD J. BARRE'I'I. DANIEL E. STRAIN. 

